Well I think most of the dire animals were in the Monster Manual as animal companions for the druid. Still, I used a fair amount of them, particularly at lower levels.
The one big hint that we have got is that either all or almost all of the monsters in the recent Desert of Desolation set of D&D Miniatures are going to be in the 4th edition Monster Manual.
You can check out the gallery here:
http://wizards.com/default.asp?x=dnd/mg/dod
One thing to notice is there are 2 dire animals, but given funny MTG-like names: Vicejaw Crocodile and Thundertusk Boar. There's also one dinosaur, also given a funny name. There are two new swarms, one lycanthrope, one regular animal, and one of the metallic dragons.
There's also some new-ish, non-classic monsters, like the Blade Spider, Rage Drake and Astral Stalker.
I agree that the 3rd edition monster manual had some rarely-used stinkers in it, mostly on Ruin Explorer's list. Still, I think they should experiment a little in the 4th ed Monster Manual 1. I want to see the classics, sure, but I'd like to see at least 5-10% new or otherwise experimental monsters.